:root {
  color-scheme: light dark;
  --canvas: #f5f5f7; --paper: #fff; --ink: #1d1d1f; --muted: #646468;
  --line: rgba(29,29,31,.13); --line-strong: rgba(29,29,31,.28);
  --accent: #1d1d1f; --on-accent: #fff; --accent-hover: #38383b;
  --soft: rgba(29,29,31,.055); --focus: rgba(29,29,31,.55); --danger: #b13d35;
  --glass: rgba(255,255,255,.74); --glass-solid: #fff; --glass-edge: rgba(255,255,255,.9);
  --shadow: 0 8px 30px rgba(0,0,0,.035); --panel: var(--paper);
}
* { box-sizing: border-box; }
html { min-width: 320px; }
[hidden] { display: none !important; }
body { margin: 0; min-height: 100vh; background: var(--canvas); color: var(--ink); font: 15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
button,input,summary { font: inherit; }
button,a,input,summary { touch-action: manipulation; -webkit-tap-highlight-color: var(--soft); }
button { min-height: 44px; padding: 10px 16px; border: 1px solid transparent; border-radius: 12px; cursor: pointer; font-weight: 600; transition: background-color 160ms ease,opacity 160ms ease; }
button:disabled { opacity: .45; cursor: default; }
button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible { outline: 2px solid var(--focus); outline-offset: 4px; }
input { min-width: 0; min-height: 44px; width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 12px; background: var(--paper); color: var(--ink); font-size: 16px; }
.primary { background: var(--accent); color: var(--on-accent); }
.quiet { background: var(--soft); color: var(--ink); border-color: var(--line); }
.danger { background: transparent; color: var(--danger); border-color: var(--line); }
.shell { max-width: 1040px; margin: auto; padding: 24px max(24px,env(safe-area-inset-right)) max(40px,env(safe-area-inset-bottom)) max(24px,env(safe-area-inset-left)); }
.top,.side,.room-setup,.game-choice,.join-entry { background: var(--glass); border: 1px solid var(--glass-edge); box-shadow: var(--shadow); -webkit-backdrop-filter: blur(18px) saturate(120%); backdrop-filter: blur(18px) saturate(120%); }
.top { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 8px 20px; min-height: 68px; padding: 10px 20px; border-radius: 22px; }
.brand { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; font-size: 15px; font-weight: 650; letter-spacing: .04em; }
.chess-symbol { display: block; width: 32px; height: 32px; flex: none; }
.room { margin-left: auto; color: var(--muted); font-size: 12px; }
.room b { margin-left: 8px; color: var(--ink); font: 600 15px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace; letter-spacing: .12em; font-variant-numeric: tabular-nums; }
.heading { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding: 28px 0 24px; }
.eyebrow { margin: 0 0 6px; color: var(--muted); font-size: 11px; letter-spacing: .09em; }
h1,h2,h3 { text-wrap: balance; }
h1 { margin: 0; font-size: 30px; line-height: 1.25; font-weight: 650; letter-spacing: -.03em; }
.identity { max-width: 65%; padding: 7px 12px; border: 1px solid var(--line); border-radius: 20px; color: var(--muted); font-size: 12px; overflow-wrap: anywhere; }
.play-area { display: grid; grid-template-columns: minmax(0,1fr) 272px; align-items: start; gap: 28px; }
.board-column { min-width: 0; }
.room-setup { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px 20px; margin-bottom: 16px; padding: 18px 20px; border-radius: 20px; }
.room-setup > div:first-child { min-width: 0; flex: 1 1 180px; }
.setup-label { display: block; margin-bottom: 4px; font-size: 11px; font-weight: 600; color: var(--muted); }
#setup-message { margin: 0; font-size: 13px; line-height: 1.7; overflow-wrap: anywhere; }
.setup-actions { display: flex; flex-wrap: wrap; gap: 8px; }
.setup-actions button { white-space: nowrap; }
.board-toolbar { display: flex; align-items: center; justify-content: space-between; min-height: 44px; gap: 16px; padding-bottom: 8px; font-size: 13px; }
.status { flex: 1; min-width: 0; margin: 0; overflow-wrap: anywhere; }
#move-count { color: var(--muted); white-space: nowrap; font-size: 12px; font-variant-numeric: tabular-nums; }
.board-footer { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 4px 12px; padding-top: 10px; color: var(--muted); font-size: 11px; }
.placement { display: flex; align-items: center; gap: 8px; min-height: 72px; padding: 12px 0; }
.placement > span,.placement > p { flex: 1; min-width: 0; margin: 0; color: var(--muted); font-size: 12px; overflow-wrap: anywhere; }
.placement button { white-space: nowrap; padding-inline: 14px; font-size: 13px; }
.placement-actions { display: flex; gap: 8px; }
.result-banner { margin: 12px 0; padding: 14px 16px; border-left: 3px solid var(--ink); border-radius: 12px; background: var(--soft); font-size: 14px; overflow-wrap: anywhere; }
.side { min-width: 0; display: grid; gap: 20px; padding: 20px; border-radius: 24px; }
.side-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; font-size: 14px; font-weight: 650; }
.side-heading span { color: var(--muted); font-size: 11px; font-weight: 400; }
#round-info { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.75; }
#round-info:empty { display: none; }
.players { display: grid; gap: 8px; }
.players > [data-seat] { display: flex; align-items: center; min-width: 0; gap: 10px; padding: 12px 10px; border: 1px solid transparent; border-radius: 14px; }
.players > [data-seat].active-turn { background: var(--soft); border-color: var(--line); }
.players [data-seat] > div { flex: 1; min-width: 0; }
.players strong { display: block; font-size: 14px; font-weight: 600; overflow-wrap: anywhere; }
.players [data-seat] > div > span { display: block; margin-top: 2px; color: var(--muted); font-size: 11px; }
.players [data-badge] { color: var(--muted); font-size: 11px; white-space: nowrap; }
.invite { display: grid; gap: 10px; padding-top: 18px; border-top: 1px solid var(--line); }
.invite label { font-size: 12px; font-weight: 600; }
.invite-code-row { display: grid; grid-template-columns: minmax(0,1fr) auto; gap: 8px; }
#invite-code { font: 600 18px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace; letter-spacing: .12em; }
.invite-code-row button { padding-inline: 10px; font-size: 11px; white-space: nowrap; }
#invite-link { font-size: 16px; }
.invite-actions { display: flex; flex-wrap: wrap; gap: 8px; }
.invite-actions button { flex: 1; padding-inline: 10px; font-size: 12px; white-space: nowrap; }
.hint { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.8; overflow-wrap: anywhere; }
#join-retry { margin-top: 10px; }
.feedback { padding: 12px 14px; border-left: 2px solid var(--ink); border-radius: 8px; background: var(--soft); font-size: 12px; line-height: 1.75; overflow-wrap: anywhere; }
.feedback.error,.join-error { color: var(--danger); border-color: var(--danger); }
.actions { display: flex; flex-wrap: wrap; gap: 8px; }
.actions button { font-size: 12px; }
.game-rules { border-top: 1px solid var(--line); padding-top: 8px; color: var(--muted); font-size: 12px; }
.game-rules summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 44px; color: var(--ink); cursor: pointer; list-style: none; }
.game-rules summary::after { content: "+"; font-size: 18px; font-weight: 400; }
.game-rules[open] summary::after { content: "−"; }
.game-rules summary::-webkit-details-marker { display: none; }
.game-rules p { margin: 0 0 12px; line-height: 1.85; }
.back-link { display: inline-flex; align-items: center; justify-self: start; gap: 12px; min-height: 44px; color: var(--muted); font-size: 12px; }
.skip { position: fixed; z-index: 30; top: 12px; left: 12px; padding: 10px 14px; border-radius: 12px; background: var(--ink); color: var(--canvas); transform: translateY(-180%); }
.skip:focus { transform: none; }
@media(hover:hover) { .primary:not(:disabled):hover { background: var(--accent-hover); } .quiet:not(:disabled):hover { background: var(--line); } .back-link:hover { color: var(--ink); } .game-rules summary:hover { text-decoration: underline; text-underline-offset: 4px; } }
@media(max-width:760px) {
  .shell { padding: 12px max(12px,env(safe-area-inset-right)) max(24px,env(safe-area-inset-bottom)) max(12px,env(safe-area-inset-left)); }
  .top { min-height: 60px; padding: 8px 14px; border-radius: 18px; gap: 4px 12px; }
  .brand { font-size: 14px; gap: 8px; }
  .chess-symbol { width: 28px; height: 28px; }
  .room b { font-size: 14px; letter-spacing: .08em; }
  .heading { padding: 20px 0 16px; gap: 8px; }
  h1 { font-size: 26px; }
  .heading .eyebrow { display: none; }
  .identity { padding: 6px 10px; font-size: 11px; }
  .play-area { grid-template-columns: minmax(0,1fr); gap: 20px; }
  .board-column { width: 100%; margin-inline: auto; }
  .room-setup { padding: 16px; margin-bottom: 12px; border-radius: 18px; }
  .room-setup > div:first-child { flex-basis: 150px; }
  .board-toolbar { gap: 12px; font-size: 12px; }
  .side { padding: 20px; gap: 16px; }
  .players { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .players > [data-seat] { display: grid; grid-template-columns: 28px minmax(0,1fr); gap: 4px 8px; padding: 10px 8px; }
  .players [data-seat] > div > span { white-space: nowrap; }
  .players [data-badge] { grid-column: 2; justify-self: start; margin-left: 0; white-space: normal; }
  .invite-code-row { grid-template-columns: minmax(0,1fr) auto; }
  .invite-code-row button { padding-inline: 14px; font-size: 12px; }
}
@media(max-width:380px) { .room-setup { display: block; } .setup-actions { margin-top: 12px; } .setup-actions button { flex: 1; } .placement { flex-wrap: wrap; } .placement > p,.placement > span { flex-basis: 100%; } .placement-actions { width: 100%; justify-content: flex-end; } .placement-actions .primary { flex: 1; } }
@media(prefers-color-scheme:dark) {
  :root { --canvas:#101012; --paper:#29292c; --ink:#f5f5f7; --muted:#b4b4ba; --line:rgba(255,255,255,.14); --line-strong:rgba(255,255,255,.32); --accent:#f5f5f7; --on-accent:#1d1d1f; --accent-hover:#dddde2; --soft:rgba(255,255,255,.065); --focus:rgba(245,245,247,.65); --danger:#f1a39d; --glass:rgba(34,34,37,.78); --glass-solid:#222225; --glass-edge:rgba(255,255,255,.1); --shadow:0 8px 30px rgba(0,0,0,.12); }
}
@supports not ((backdrop-filter:blur(1px)) or (-webkit-backdrop-filter:blur(1px))) { .top,.side,.room-setup,.game-choice,.join-entry { background: var(--glass-solid); } }
@media(prefers-reduced-transparency:reduce),(prefers-contrast:more) { .top,.side,.room-setup,.game-choice,.join-entry { background:var(--glass-solid); -webkit-backdrop-filter:none; backdrop-filter:none; box-shadow:none; border-color:var(--line-strong); } }
@media(prefers-reduced-motion:reduce) { button,a { transition:none; } }